 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.model;

 import org.eclipse.jface.viewers.ITreeContentProvider;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.ui.internal.util.Util;

 /**
  * Tree content provider for objects that can be adapted to the interface
  * {@link org.eclipse.ui.model.IWorkbenchAdapter IWorkbenchAdapter}.
  * <p>
  * This class may be instantiated, or subclassed.
  * </p>
  *
  * @see IWorkbenchAdapter
  * @since 3.0
  */
 public class BaseWorkbenchContentProvider implements ITreeContentProvider {

     /**
      * Creates a new workbench content provider.
      *
      */
     public BaseWorkbenchContentProvider() {
         super();
     }

     /* (non-Javadoc)
      * Method declared on IContentProvider.
      */
     public void dispose() {
         // do nothing
 }

     /**
      * Returns the implementation of IWorkbenchAdapter for the given
      * object. Returns null if the adapter is not defined or the
      * object is not adaptable.
      * <p>
      * </p>
      *
      * @param element the element
      * @return the corresponding workbench adapter object
      */
     protected IWorkbenchAdapter getAdapter(Object element) {
         return (IWorkbenchAdapter)Util.getAdapter(element, IWorkbenchAdapter.class);
     }

     /* (non-Javadoc)
      * Method declared on ITreeContentProvider.
      */
     public Object [] getChildren(Object element) {
         IWorkbenchAdapter adapter = getAdapter(element);
         if (adapter != null) {
             return adapter.getChildren(element);
         }
         return new Object [0];
     }

     /* (non-Javadoc)
      * Method declared on IStructuredContentProvider.
      */
     public Object [] getElements(Object element) {
         return getChildren(element);
     }

     /* (non-Javadoc)
      * Method declared on ITreeContentProvider.
      */
     public Object getParent(Object element) {
         IWorkbenchAdapter adapter = getAdapter(element);
         if (adapter != null) {
             return adapter.getParent(element);
         }
         return null;
     }

     /* (non-Javadoc)
      * Method declared on ITreeContentProvider.
      */
     public boolean hasChildren(Object element) {
         return getChildren(element).length > 0;
     }

     /* (non-Javadoc)
      * Method declared on IContentProvider.
      */
     public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
         // do nothing
 }

 }

